The present invention relates to an apparatus for controlling the amount of transmission of light having a high energy density through a desired optical path.
I have proposed an optical transmission system which is available for utilizing the solar energy for illumination and other various purposes. With this system, the solar energy is converged by a lens or the like into an optical conductor and transmitted therethrough to a desired location for a specific application. The lens is constructed to automatically follow the movement of the sun and, accordingly, the sunlight is constantly guided to the desired location throughout the duration of sunshine. It is sometimes desired, however, to temporarily shut off the sunrays coming into the intended location through the optical transmission system. For example, while the converged sunlight may comfort the old persons who are spending years in sickbeds if guided by the system into their rooms, it will rather put them to annoyance when they want to sleep in the daytime. Although a simple opaque member is usable to shut off the light, it will be heated or even burned due to such an energy density of the light. Additionally, it the opaque member has reflective surfaces, the member will reflect the light back into the lens or the like to adversely affect it.